1. Field of the Invention
This invention relates to an insoluble powder, in particular, skin barrier function recovering effect and skin roughening preventing and improving effect of the same powder.
2. Prior Art
The skin is anatomically divided to epidermis, derma, and subcutaneous tissue. And said epidermis is composed of basal layer, spinosum layer, granular layer and horny layer. The horny layer of the epidermis is very thin and the thickness is below 20 μm. Accordingly drying and skin roughness are easy to be caused by the external stimulation such as ultraviolet rays, drying, air pollution, and microorganism, and internal factors such as sebum excretion, sweat gland functions, epidermis metabolism, and aging. Hitherto it was carried out that amino acids, polysaccharides, lipids, natural polymeric compounds and so on having high moisturizing effect and water retention effect are blended to skin external composition.
However, the skin external composition that blended a large quantity of these moisturizing agents tends to become sticky, so sometimes happen the harmful effect on use.
On the other hand, it is considered that, if a solid not permeating into the interior of a skin such as a powder can be used as an active ingredient for improving skin roughening, safety can be further enhanced.
The present invention was done in view of the previous problems, and an object thereof is to provide an insoluble powder having excellent skin barrier function recovering effect and skin roughening preventing and improving effect, and a skin external composition containing the same.